THE UNITED KINGDOM INFRARED TELESCOPE
ANNUAL REPORT
1998

Introduction

S.J. Warren, Chairman, UKIRT Board

Astronomers are only just getting used to the luxury of being able to expect sub-arcsecond seeing for their observations. Several telescopes around the world are now reporting median seeing of about 0.6" to 0.7". Astronomers return from these telescopes delighted with the quality of their data: but we read in this report that at UKIRT ``users now tend to regard 0.7" as poor seeing''! No-one can fail to be impressed when they read that ``Over the month of September the median corrected image was 0.265" and the worst image had FWHM 0.563''. As a consequence of the Upgrades Programme, which was essentially completed in 1998, UKIRT probably now enjoys the best image quality of any ground-based telescope.

The superb image quality has benefited several imaging programmes, notably world-leading surveys for brown dwarfs, studies of galaxy clusters, and the search for the highly reddened counterparts of submillimetre-bright galaxies detected with SCUBA on the JCMT. The installation of the UFTI camera with a pixel scale of 0.09" realises the full gains from the excellent seeing. The good seeing also benefits spectroscopy and CGS4 continues to be used for just over half of the observing time. A search for Earth-mass companions to brown dwarfs using the echelle grating is one of several spectroscopic highlights.

As the 8-metre class telescopes on Mauna Kea become equipped with infrared instruments, UKIRT must adapt its mode of operation and instrument suite to continue to be at the forefront of infrared astronomy. A successful 1998 programme of observations of -ray bursts was possible because of UKIRT's system of reactive scheduling, and this can be seen as the first step towards the desired goal of fully-flexible scheduling that will match the observing programme to the conditions. On the instrumentation side, momentum towards the construction of a wide-field imager for UKIRT has been growing. The concept is for four 2048 x 2048 arrays covering 0.25 deg² per exposure. Wide-field JHK surveys several magnitudes deeper than 2MASS and DENIS will open up a vast new region of parameter space for exploration.

1998 saw the departure of Tom Geballe after 17 years service. During his long tenure as Head of Operations the fraction of time lost due to instrument problems has been minimal, and the quality of support for visiting astronomers has been outstanding. Tom seemed to be available to observers at all hours of day and night. It is a pleasure to record here the gratitude of the many astronomers who observed at UKIRT during his tenure, and to pass on our best wishes to him in his new post at Gemini.